Urine: Composition and Function
Urine can be a vital evidence in forensic investigations into allegations of sexual assault and harassment. The presence of urine in such cases may indicate that the victim was incapacitated with drugs or alcohol, and they may not have been able to control their bladder. Additionally, urine samples are often collected and analysed to detect the presence of drugs or alcohol in a person's body in cases of drug abuse, driving under the influence (DUI), and other criminal investigations.
COMPOSITION OF URINE
Urine is a liquid waste product of the body composed primarily of water (~95%), and a combination of dissolved salts and organic compounds (~5%) including urea, uric acid, creatinine, sodium, potassium, chloride, calcium, and magnesium. It also contains trace amounts of metabolic byproducts such as hormones, proteins, medications, drugs, and other substances.
Urine typically has a yellowish-amber color. The color of urine can also provide information about its composition. Clear or pale yellow urine typically indicates that a person is well-hydrated, while darker yellow or amber-colored urine can indicate dehydration. Urine that is dark brown or black can indicate the presence of blood or other substances that are breaking down in the body.
The pH of urine is also an important aspect of its composition, which can be used to evaluate a person's acid-base balance. Normal urine pH is around 6.0 to 7.5, which is slightly acidic. pH levels outside of this range can indicate certain medical conditions, such as urinary tract infections or metabolic disorders.
FUNCTIONS OF URINE
Waste elimination: The primary function of urine is the elimination of waste products that are generated as a result of metabolism and other physiological processes. These waste products include nitrogenous compounds such as urea, creatinine, and uric acid, which are produced by the breakdown of proteins and nucleic acids. These waste products are toxic if they accumulate in the body.
Maintaining fluid balance: The kidneys play a crucial role in regulating the body's fluid balance by adjusting the amount of urine produced. When the body is dehydrated, the kidneys reabsorb more water from the filtrate, resulting in a decrease in urine output. Conversely, when the body is overhydrated, the kidneys produce more urine in order to excrete the excess water. This helps to maintain the appropriate balance of fluids in the body and prevent dehydration or overhydration.
Regulating electrolyte balance: Urine also plays a role in regulating the balance of electrolytes in the body. Electrolytes, such as sodium, potassium, and chloride, are important for maintaining the proper functioning of the body's cells and organs. The kidneys can reabsorb or excrete these electrolytes in order to maintain the appropriate balance, which is essential for many physiological processes. For example: an imbalance of electrolytes can lead to conditions such as hypertension or hypokalemia.
Diagnostic tool: Urine is a useful diagnostic tool that can be used to detect a wide range of medical conditions. Changes in the colour, odour, or concentration of urine can indicate certain medical conditions, such as dehydration, kidney problems, or urinary tract infections. Additionally, urine tests can be used to detect the presence of abnormal substances, such as glucose, in the urine, which can indicate conditions such as diabetes or kidney disease.